Cleaner head

ABSTRACT

The present invention relates to a cleaner head including: a front housing and a rear housing disposed side by side on front and rear sides thereof respectively, the rear housing having an air outlet formed thereon; a front brush rotatably disposed on the front housing in such a manner as to be exposed from the underside of the front housing; a rear brush rotatably disposed the rear housing in such a manner as to be exposed from the underside of the rear housing; driving motors built in the rear housing to rotate the front brush and the rear brush through a power transmission mechanism; a lifting unit disposed on one side of the rear housing to move up and down the front housing with respect to the rear housing in a hinged manner; and a sensing part disposed on any one of the front housing and the rear housing and a part to be sensed disposed on the other, wherein when the front housing is stretched out with respect to the rear housing, rotating power is transferred to the front brush from the corresponding driving motor, and when the front housing is lifted, the rotating power transferred to the front brush cuts off to stop the rotation of the front brush.

TECHNICAL FIELD

The present invention relates to a cleaner head, and more particularly, to a cleaner head capable of lifting a front brush.

REARGROUND ART

Generally, a vacuum cleaner includes a body having a fan motor disposed at the inside thereof to generate a suction force, an extension tube at one end thereof connected to a suction port of the body, and a suction head disposed on the free end of the extension tube to suck foreign matters like dust through the suction force of the fan motor.

Recently, a vacuum cleaner, which is configured to have a brush rotatably protruding from the underside of the suction head and a driving motor for driving the brush, has been popularly introduced.

Further, a cleaner head, which is provided with two brushes having different characteristics disposed side by side in front and rear directions to provide a double brush structure, has been proposed, thereby enhancing agitation effects of foreign matters.

In case of the conventional cleaner head, however, the two brushes are configured to always come into contact with the floor, thereby failing to obtain optimal foreign matter sucking effects according to characteristics of the surface of the floor.

For example, if a surface of a carpet is cleaned with a cleaner head having a double brush structure consisting of a flannel brush and a straight hair brush, the flannel brush does not provide cleaning effects substantially and further pressurizes the surface of the carpet, thereby resulting in the reduction of the cleaning effects.

According to the conventional cleaner head, furthermore, the two brushes are kept coming into contact with the floor, thereby undesirably increasing an area occupying the floor.

DISCLOSURE Technical Problem

Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a cleaner head that is configured to lift a front brush if necessary, thereby optimally maintaining cleaning effects and reducing an area occupying the floor.

It is another object of the present invention to provide a cleaner head that is configured to cut off rotating power when a front brush is lifted, thereby avoiding unnecessary power consumption and preventing occurrence of vibrations of the cleaner head.

Technical Solution

To accomplish the above-mentioned objects, according to the present invention, there is provided a cleaner head including: a front housing and a rear housing disposed side by side on front and rear sides thereof respectively, the rear housing having an air outlet formed thereon; a front brush rotatably disposed on the front housing in such a manner as to be exposed from the underside of the front housing; a rear brush rotatably disposed the rear housing in such a manner as to be exposed from the underside of the rear housing; driving motors built in the rear housing to rotate the front brush and the rear brush through a power transmission mechanism; and a lifting unit disposed on one side of the rear housing to move up and down the front housing with respect to the rear housing in a hinged manner, wherein when the front housing is stretched out with respect to the rear housing, rotating power is transferred to the front brush from the driving motor, and when the front housing is lifted, the rotating power to the front brush cuts off to stop the rotation of the front brush.

According to the present invention, desirably, the cleaner head further includes a sensing part disposed on any one of the front housing and the rear housing and a part to be sensed disposed on the other.

According to the present invention, desirably, any one of the sensing part and the part to be sensed is disposed on the inner side of one side frame of the front housing, and the other is disposed on one side surface of the rear housing, so that when the front housing is stretched out with respect to the rear housing, the sensing part and the part to be sensed are facingly arranged close to each other.

According to the present invention, desirably, the sensing part is a hall sensor and the part to be sensed is a magnet.

According to the present invention, desirably, the sensing part is a light receiving sensor and the part to be sensed is a light source.

According to the present invention, desirably, on-off switches are disposed between the front housing and the rear housing respectively.

According to the present invention, desirably, the lifting unit includes: a housing frame disposed on one side of the rear housing; a driving and rotating piece rotatably coupled to the housing frame, coupled to one side of the front housing, and having first gear teeth formed on at least a portion of a periphery thereof; an intermediate gear rotatably coupled to the housing frame and having second gear teeth engaging with the first gear teeth; a locking and supporting piece extended from the intermediate gear in a direction of a rotating shaft of the intermediate gear; a rotating and locking piece rotatably coupled to the housing frame and intermittently engageable with the locking and supporting piece; and a spring connected at one end thereof to the driving and rotating piece and at the other end thereof to the housing frame.

According to the present invention, desirably, the locking and supporting piece has a locking threshold part formed thereon in a circumferential direction thereof, and the rotating and locking piece has a hook formed on one end thereof in such a manner as to be lockable on the locking threshold part.

According to the present invention, desirably, the lifting unit further includes an operating pedal hinge-movable up and down with respect to the housing frame in such a manner as to come into contact with the rotating and locking piece to allow the rotating and locking piece to be reciprocatingly hinge-movable to the housing frame.

According to the present invention, desirably, one end of the spring is connected to the driving and rotating piece by means of a load connecting piece.

According to the present invention, desirably, the driving and rotating piece and the load connecting piece are coupled to each other in a hinge-movable manner.

According to the present invention, desirably, the housing frame has a hinge part extended in a direction toward the longitudinal center of the cleaner head in such a manner as to be hinge-coupled to the operating pedal.

According to the present invention, desirably, the hinge part has hinge grooves open upward on top thereof, and the operating pedal has a hinge pin disposed on the front top side thereof in such a manner as to be hinge-coupled to the hinge grooves.

According to the present invention, desirably, the rotating and locking piece has a locking groove formed on one end thereof in such a manner as to be open on the underside thereof, and the operating pedal has a locking protrusion extended laterally from the front lower end thereof in such a manner as to be inserted into the locking groove.

According to the present invention, desirably, a compression spring is connected between a point spaced downward from the hinge grooves of the housing frame and a point spaced downward from the hinge pin of the operating pedal.

According to the present invention, desirably, a damping gear is rotatably coupled to the housing frame in such a manner that the damping gear is engaged with the intermediate gear.

According to the present invention, desirably, the driving and rotating piece includes a first coupling portion protruding from the outer surface thereof in such a manner as to have the same center as the rotary shaft of the rear brush and a second coupling portion formed spaced apart from the first coupling portion, and the front housing includes a third coupling portion and a fourth coupling portion formed on one side end thereof in such a manner as to be coupled correspondingly to the first coupling portion and the second coupling portion.

Advantageous Effects

According to the present invention, the cleaner head is configured to lift the front brush or to stretch the front brush to come into contact with the floor as needed, thereby optimally maintaining cleaning effects according to places, minimizing a resistance occurring while moving, and reducing an area occupying the floor while being kept in a given place.

According to the present invention, moreover, the rotating power cuts off when the front brush is lifted, thereby suppressing unnecessary power consumption and preventing the whole cleaner head from being vibrated due to the rotation of the front brush lifted in the air.

In addition, the cleaner head according to the present invention is configured to press the operating pedal by means of a user's hand or foot to lift the front brush, thereby providing many conveniences of use thereof.

Further, the cleaner head according to the present invention is configured to have the damping gear disposed freely rotatable on the housing frame in such a manner as to engage with the intermediate gear, thereby avoiding the breakage of the components due to abrupt lifting of the front housing by the spring.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a cleaner head according to the present invention.

FIG. 2 is an exploded perspective view showing the cleaner head according to the present invention.

FIG. 3 is an exploded perspective view showing a right side of the cleaner head according to the present invention, wherein a front housing and a side case are separated from the cleaner head.

FIG. 4 is an exploded perspective view showing a left side of the cleaner head according to the present invention, wherein the front housing and the side case are separated from the cleaner head.

FIG. 5 is a perspective view showing a front side of a lifting unit of the cleaner head of FIG. 2.

FIG. 6 is a partially exploded perspective view showing the front side of the lifting unit of the cleaner head according to the present invention.

FIG. 7 is a perspective view showing a rear side of a portion of the lifting unit of the cleaner head according to the present invention.

FIG. 8 is a side view showing the lifting unit of the cleaner head according to the present invention, wherein a front brush is stretched out.

FIG. 9 is a side view showing the lifting unit of the cleaner head according to the present invention, wherein the front brush is lifted.

MODE FOR INVENTION

Hereinafter, an explanation on a cleaner head according to the present invention will be in detail given with reference to the attached drawings.

As shown in FIGS. 1 to 4, a cleaner head 1000 according to the present invention includes: a front housing 100 and a rear housing 200 disposed side by side on front and rear sides thereof respectively, the rear housing 200 having an air outlet 210 formed thereon; a front brush 700 rotatably disposed on the front housing 100 in such a manner as to be exposed from the underside of the front housing 100; a rear brush 800 rotatably disposed the rear housing 200 in such a manner as to be exposed from the underside of the rear housing 200; driving motors 500 built in the rear housing 200 to rotate the front brush 700 and the rear brush 800 through a power transmission mechanism 600; a lifting unit 300 disposed on one side of the rear housing 200 to move up and down the front housing 100 with respect to the rear housing 200 in a hinged manner; and a part to be sensed 150 disposed on the front housing 100 and a sensing part 250 disposed on the rear housing 200, wherein when the front housing 100 is stretched out with respect to the rear housing 200, rotating power is transferred to the front brush 700 from the driving motor 500, and when the front housing 100 is lifted, the rotating power to the front brush 700 cuts off to stop the rotation of the front brush 700.

The front brush 700 and the rear brush 800 are driven by means of the driving motors 500, thereby making it possible to perform the above-mentioned operations.

Of course, it is also possible that the sensing part 250 is disposed on the front housing 100 and the part to be sensed 150 is disposed on the rear housing 200.

That is, when the front brush 700 is lifted and is not used for cleaning, in detail, the rotating power cuts off to prevent additional power consumption.

Particularly, the part to be sensed 150 is disposed on the inner side of one side frame 190 of the front housing 100, and the sensing part 250 is disposed on one side surface of the rear housing 200, so that when the front housing 100 is stretched out with respect to the rear housing 200, the part to be sensed 150 and the sensing part 250 are facingly arranged close to each other to allow supply of the rotating power to be maintained by means of a controller (not shown).

But, when the front housing 100 is stretched out with respect to the rear housing 200, of course, it is possible that the part to be sensed 150 and the sensing part 250 become distant from each other to allow supply of the rotating power to be maintained by means of the controller.

The sensing part 250 can be a hall sensor and the part to be sensed 150 can be a magnet.

Otherwise, the sensing part 250 can be a light receiving sensor and the part to be sensed 150 can be a light source.

According to another embodiment of the present invention, on-off switches (not shown) are disposed between the front housing 100 and the rear housing 200 in such a manner as to be connected physically (mechanically) to each other or to cut off their connection, thereby continuously operating the driving motor 500 connected to the front brush 700 or stopping the operation of the driving motor 500.

The on-off switches can be formed of limit switches, and of course, they may be used with various switches capable of controlling electric power through their physical contact/separation according to the rotation of the front housing 100.

In addition, various components capable of controlling electric power through a hinge movable member may be used as the sensing part 250 and the part to be sensed 150.

On the other hand, the front housing 100 can move up and down with respect to the rear housing 200 by means of the lifting unit 300. As needed, the front brush 700 disposed on the front housing 100 is stretched out to come into contact with the floor or is lifted to allow only the rear brush 800 disposed on the rear housing 200 to come into contact with the floor.

For example, if the front brush 700 is a roll type brush made of soft flannel and the rear brush 800 is made of a tough straight hair or rubber strip or both straight hair and rubber strip, the front brush 700 is lifted because the front brush 700 does not provide cleaning effects substantially at the time when a carpet having much hair raised high is cleaned, so that while the cleaner head 1000 is moving for cleaning, a resistance caused therefrom can be reduced.

In more detail, as shown in FIGS. 5 to 7, the lifting unit 300 includes: a housing frame 310 disposed on one side of the rear housing 200; a driving and rotating piece 320 rotatably coupled to the housing frame 310, coupled to one side of the front housing 100, and having first gear teeth 321 formed on at least a portion of a periphery thereof; an intermediate gear 330 rotatably coupled to the housing frame 310 and having second gear teeth 331 engaging with the first gear teeth 321; a locking and supporting piece 340 extended from the intermediate gear 330 in a direction of a rotating shaft of the intermediate gear 330; a rotating and locking piece 350 rotatably coupled to the housing frame 310 and intermittently engageable with the locking and supporting piece 340; and a spring 370 connected at one end thereof to the driving and rotating piece 320 and at the other end thereof to the housing frame 310.

That is, in a state wherein the front housing 100 is stretched out and front brush 700 comes into contact with the floor, as shown in FIG. 8, the spring 370 is kept pulled out, so that it tends to be returned to its original position.

However, the rotating and locking piece 350 is hooked onto the locking and supporting piece 340, and accordingly, the spring 370 is not returned to its original position.

That is, in the state wherein the front housing 100 is stretched out, the spring 370 is in a tight state.

Especially, the locking and supporting piece 340 has a locking threshold part 341 formed thereon in a circumferential direction thereof, and the rotating and locking piece 350 has a hook 351 formed on one end thereof in such a manner as to be lockable on the locking threshold part 341, thereby desirably providing a reliable locking structure.

The locking and supporting piece 340 desirably has an arc-shaped peripheral surface extended from the locking threshold part 341.

That is, as described above, in the state where the front housing 100 is stretched out and front brush 700 comes into contact with the floor, the part to be sensed 150 disposed on the inner side of one side frame 190 of the front housing 100 is facingly located close to the sensing part 250 disposed on one side surface of the rear housing 200, and supply of the rotating power is maintained by means of the controller.

The lifting unit 300 further includes an operating pedal 360 hinge-movable up and down with respect to the housing frame 310 in such a manner as to come into contact with the rotating and locking piece 350 to allow the rotating and locking piece 350 to be reciprocatingly hinge-movable to the housing frame 310.

If the operating pedal 360 is pressed down, as shown in FIG. 9, the operating pedal 360 rotates with respect to the housing frame 310 to come into contact with the rotating and locking piece 350, so that the rotating and locking piece 350 rotates with respect to the housing frame 310 to cause the hook 351 to escape from the locking threshold part 341 of the locking and supporting piece 340.

Accordingly, the driving and rotating piece 320 rotates in a clockwise direction by means of the restoring force of the spring 370, so that the front housing 100 coupled to the driving and rotating piece 320 rotates in the clockwise direction with respect to the coaxial shaft to the rear brush 800 and is thus lifted.

In this case, the part to be sensed 150 disposed on the inner side of one side frame 190 of the front housing 100 gets farther away from the sensing part 250 disposed on one side surface of the rear housing 200, and accordingly, the part to be sensed 150 cannot be sensed by the sensing part 250, so that the rotating power cuts off by means of the controller to stop the rotation of the front brush 700.

Accordingly, the front brush 700 can be prevented from being unnecessarily rotated, thereby avoiding unnecessary power consumption, and further, the cleaner head 1000 can be prevented from being vibrated due to the rotation of the front brush 700 lifted from the floor.

Instead of the operating pedal 360, other components such as a handle, lever, or pressing switch may be adopted to hinge-rotate the rotating and locking piece 350, and they have similar functions to each other, from which it will be understood that they are equivalent components in view of the their analysis of right.

Desirably, one end of the spring 370 is connected to the driving and rotating piece 320 by means of a load connecting piece 380.

The load connecting piece 380 protrudes from the peripheral surface of the driving and rotating piece 320 to allow the spring 370 to produce a maximum moment from the driving and rotating piece 320, and desirably, the spring 370 is connected to the protruding portion of the load connecting piece 380.

Particularly, the driving and rotating piece 320 and the load connecting piece 380 are coupled to each other in a hinge-movable manner, thereby in advance preventing a failure caused due to the change of the spring 370 in posture from occurring during the rotation of the driving and rotating piece 320.

Further, the housing frame 310 has a hinge part 390 extended in a direction toward the longitudinal center of the cleaner head 1000 in such a manner as to be hinge-coupled to the operating pedal 360.

Accordingly, the hinge part 390 is prevented from protruding from the side of the cleaner head 1000 to provide an excellent outer appearance of the cleaner head 1000 and to suppress an area of the cleaner head 100 occupying the floor from being increased.

In this case, the hinge part 390 has hinge grooves 391 open upward on top thereof, and the operating pedal 360 has a hinge pin 361 disposed on the front top side thereof in such a manner as to be hinge-coupled to the hinge grooves 391, so that the operating pedal 360 is smoothly hinge-movable up and down.

So as to allow the rotating and locking piece 350 to easily rotate while the operating pedal 360 is hinge-moving, further, the rotating and locking piece 350 has a locking groove 352 formed on one end thereof in such a manner as to be open on the underside thereof, and the operating pedal 360 has a locking protrusion 362 extended laterally from the front lower end thereof in such a manner as to be inserted into the locking groove 352.

So as to allow the operating pedal 360 to be returned to its original position after pressed down, as shown in FIGS. 6 and 7, a compression spring 318 is connected between a point p1 spaced downward from the hinge grooves 391 of the housing frame 310 and a point p2 spaced downward from the hinge pin 361 of the operating pedal 360.

Since the hook 351 escapes upward from the locking threshold part 341 of the locking and supporting piece 340, in this case, the hook 351 is maintained in a state of coming into contact with the periphery of the locking and supporting piece 340, while an upward restoring force is being applied to the operating pedal 360.

On the other hand, a damping gear 338 is rotatably coupled to the housing frame 310 in such a manner that the damping gear 338 is engaged with the intermediate gear 330.

The damping gear 338 is a mechanical component giving an appropriate resistance to rotation and is adapted to engage with the intermediate gear 330, thereby avoiding the breakage of the components due to abrupt lifting of the front housing 100 by the spring 370.

Further, the driving and rotating piece 320 includes a first coupling portion 325 protruding from the outer surface thereof in such a manner as to have the same center as the rotary shaft of the rear brush 800 and a second coupling portion 326 formed spaced apart from the first coupling portion 325, and the front housing 100 includes a third coupling portion 105 and a fourth coupling portion 106 formed on one side end thereof in such a manner as to be coupled correspondingly to the first coupling portion 325 and the second coupling portion 326, so that the front housing 100 can surely rotate engagingly with the rotation of the driving and rotating piece 320.

Coupling between the first coupling portion 325 and the third coupling portion 105 and between the second coupling portion 326 and the fourth coupling portion 106 is carried out by means of fastening means C such as screws.

The power transmission mechanism 600 for connecting the driving motors 500 to the front brush 700 and the rear brush 800 includes pulleys and a timing belt, and otherwise, it may include a gear train in which gears continuously engaged with each other.

A reference numeral 900 not explained in FIGS. 5 and 6 indicates a side case.

Hereinafter, an explanation on the lifting operation of the double brush in the cleaner head according to the present invention will be in detail given with reference to FIGS. 8 and 9.

First, in a state wherein the front housing 100 is stretched out and front brush 700 comes into contact with the floor, as shown in FIG. 8, the front brush 700 and the rear brush 800 at the same time rotate by means of the driving motors 500 to remove foreign matters from the floor.

The removed foreign matters are sucked through the air outlet 210 of the rear housing 200 and then accommodated in a separate dust tank (not shown).

In this case, the spring 370, which is connected between the driving and rotating piece 320 and the housing frame 310 of the lifting unit 300, is kept tightly pulled out, so that it tends to be returned to its original position.

However, the hook 351 of the rotating and locking piece 350 is hooked on the locking threshold part 341 of the locking and supporting piece 340, so that the spring 370 is not returned to its original position.

That is, in the state wherein the front housing 100 is stretched out, the spring 370 is kept tightly pulled out.

As described above, in the state where the front housing 100 is stretched out and front brush 700 comes into contact with the floor, the part to be sensed 150 disposed on the inner side of one side frame 190 of the front housing 100 is facingly located close to the sensing part 250 disposed on one side surface of the rear housing 200, and the supply of the rotating power is maintained by means of the controller.

If the operating pedal 360 is pressed down, on the other hand, the locking protrusion 353 of the operating pedal 360 pushes the inner surface of the locking groove 352 of the rotating and locking piece 350, as shown in FIG. 9, so that the rotating and locking piece 350 is hinge-moved in the clockwise direction to allow the hook 351 to escape from the locking threshold part 341 of the locking and supporting piece 340.

Accordingly, the driving and rotating piece 320 rotates in the clockwise direction by means of the restoring force of the spring 370, and the intermediate gear 330 engaged with the driving and rotating piece 320 rotates in a counterclockwise direction.

As a result, the front housing 100 coupled to the driving and rotating piece 320 also rotates in the clockwise direction with respect to the coaxial shaft to the rear brush 800 and is thus lifted.

Like this, if the front housing 100 is maintained in a lifted state, the part to be sensed 150 disposed on the inner side of one side frame 190 of the front housing 100 gets farther away from the sensing part 250 disposed on one side surface of the rear housing 200, and accordingly, the part to be sensed 150 cannot be sensed by the sensing part 250, so that the rotating power cuts off by means of the controller to stop the rotation of the front housing 100.

At this time, the damping gear 338 engaged with the intermediate gear 330 rotates engagingly with the intermediate gear 330 to allow the front housing 100 to be slowly lifted, thereby preventing the front housing 100 from being shockingly lifted.

If a pressing load applied to the operating pedal 360 is released, further, a returning force tending to be restored to an original position is applied to the operating pedal 360 by means of the compression spring 318.

In the state where the locking state of the hook 351 on the locking threshold part 341 is released, accordingly, the hook 351 is just pressed against the outer surface of the locking and supporting piece 340, but the hook 351 cannot stop the rotation of the locking and supporting piece 340 and the intermediate gear 330.

So as to change the lifted state of the front housing 100 into the stretched state on the floor, on the other hand, the front housing 100 is just rotated in the opposite direction to the lifted direction.

In more detail, if an user rotates the front housing 100 to the stretched state, the driving and rotating piece 320 coupled to the front housing 100 rotates in the counterclockwise direction, and the load connecting piece 380 connected to the driving and rotating piece 320 rotates to allow the spring 370 to be pulled out with respect to the housing frame 310.

As the driving and rotating piece 320 rotates, further, the intermediate gear 330 and the locking and supporting piece 340 engaged with the driving and rotating piece 320 rotate in the clockwise direction, so that the locking threshold part 341 formed on the locking and supporting piece 340 is locked on the hook 351 of the rotating and locking piece 350.

Accordingly, the front housing 100 coupled to the driving and rotating piece 320 is thus stretched out on the floor and front brush 700 comes into contact with the floor.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. 

1. A cleaner head comprising: a front housing and a rear housing disposed side by side on front and rear sides thereof respectively, the rear housing having an air outlet formed thereon; a front brush rotatably disposed on the front housing in such a manner as to be exposed from the underside of the front housing; a rear brush rotatably disposed on the rear housing in such a manner as to be exposed from the underside of the rear housing; driving motors built in the rear housing to rotate the front brush and the rear brush through a power transmission mechanism; and a lifting unit disposed on one side of the rear housing to move up and down the front housing with respect to the rear housing in a hinged manner, wherein when the front housing is stretched out with respect to the rear housing, rotating power is transferred to the front brush from the driving motor, and when the front housing is lifted, the rotating power to the front brush cuts off to stop the rotation of the front brush.
 2. The cleaner head according to claim 1, further comprising a sensing part disposed on any one of the front housing and the rear housing and a part to be sensed disposed on the other.
 3. The cleaner head according to claim 2, wherein any one of the sensing part and the part to be sensed is disposed on the inner side of one side frame of the front housing, and the other is disposed on one side surface of the rear housing, so that when the front housing is stretched out with respect to the rear housing, the sensing part and the part to be sensed are facingly arranged close to each other.
 4. The cleaner head according to claim 2, wherein the sensing part is a hall sensor and the part to be sensed is a magnet.
 5. The cleaner head according to claim 2, wherein the sensing part is a light receiving sensor and the part to be sensed is a light source.
 6. The cleaner head according to claim 1, wherein on-off switches are disposed between the front housing and the rear housing respectively.
 7. The cleaner head according to claim 1, wherein the lifting unit comprises: a housing frame disposed on one side of the rear housing; a driving and rotating piece rotatably coupled to the housing frame, coupled to one side of the front housing, and having first gear teeth formed on at least a portion of a periphery thereof; an intermediate gear rotatably coupled to the housing frame and having second gear teeth engaging with the first gear teeth; a locking and supporting piece extended from the intermediate gear in a direction of a rotating shaft of the intermediate gear; a rotating and locking piece rotatably coupled to the housing frame and intermittently engageable with the locking and supporting piece; and a spring connected at one end thereof to the driving and rotating piece and at the other end thereof to the housing frame.
 8. The cleaner head according to claim 7, wherein the locking and supporting piece has a locking threshold part formed thereon in a circumferential direction thereof, and the rotating and locking piece has a hook formed on one end thereof in such a manner as to be lockable on the locking threshold part.
 9. The cleaner head according to claim 7, wherein the lifting unit further comprises an operating pedal hinge-movable up and down with respect to the housing frame in such a manner as to come into contact with the rotating and locking piece to allow the rotating and locking piece to be reciprocatingly hinge-movable to the housing frame.
 10. The cleaner head according to claim 7, wherein one end of the spring is connected to the driving and rotating piece by means of a load connecting piece.
 11. The cleaner head according to claim 10, wherein the driving and rotating piece and the load connecting piece are coupled to each other in a hinge-movable manner.
 12. The cleaner head according to claim 9, wherein the housing frame has a hinge part extended in a direction toward the longitudinal center of the cleaner head in such a manner as to be hinge-coupled to the operating pedal.
 13. The cleaner head according to claim 12, wherein the hinge part has hinge grooves open upward on top thereof, and the operating pedal has a hinge pin disposed on the front top side thereof in such a manner as to be hinge-coupled to the hinge grooves.
 14. The cleaner head according to claim 12, wherein the rotating and locking piece has a locking groove formed on one end thereof in such a manner as to be open on the underside thereof, and the operating pedal has a locking protrusion extended laterally from the front lower end thereof in such a manner as to be inserted into the locking groove.
 15. The cleaner head according to claim 13, wherein a compression spring is connected between a point spaced downward from the hinge grooves of the housing frame and a point spaced downward from the hinge pin of the operating pedal.
 16. The cleaner head according to claim 7, wherein a damping gear is rotatably coupled to the housing frame in such a manner that the damping gear is engaged with the intermediate gear.
 17. The cleaner head according to claim 7, wherein the driving and rotating piece comprises a first coupling portion protruding from the outer surface thereof in such a manner as to have the same center as the rotary shaft of the rear brush and a second coupling portion formed spaced apart from the first coupling portion, and the front housing comprises a third coupling portion and a fourth coupling portion formed on one side end thereof in such a manner as to be coupled correspondingly to the first coupling portion and the second coupling portion. 